Home Soundproofing

Want to live in a quieter home? Read this article for some great ideas on how to tone down the hubbub both inside and outside your house. From noisy plumbing to raucous neighbors, we'll show you how to create the peace and quiet we all want in our homes.

A few simple concepts about noise

Fig. B: Eliminate gaps

The continuous, tight bead
of caulk on the side of the window
blocks noise, while the uncaulked
lower edge lets sound enter unabated.

Fig. C: Use more mass

Because of its greater mass,
the poured concrete lower wall is less
prone to vibrate and will block more
sound than the lightweight upper
wall—even when insulated.

Fig. D: Isolate vibration

The small cork or rubber
pad helps isolate the vibration of the
washing machine (right), while the
dryer leg resting directly on the floor
passes vibration (and noise) on.

Fig. E: Quiet Interior Noise

Diminish noise levels using a variety of
techniques, including sealing off airborne sound paths,
adding mass to walls and isolating sounds generated
via the plumbing and heating systems.

Noise is simply airborne vibration.
What we perceive as noise traveling
“through” a wall or other object is
actually sound waves causing the wall
to vibrate, then this vibrating wall
making the air on its other side
vibrate. Regardless of how it travels,
noise reaches its final destination—
our ears—as airborne sound. That’s
what ears are, vibration receivers.
Since noise travels primarily through
air, the best way to block it is to put
something in its path. To be most
effective at blocking sound, the material
needs three qualities. It should be
gapless (Fig. B), since sound will
sneak through even the smallest
cracks and holes. It should have a lot
of mass (Fig. C), so it’s less prone to
vibrate and pass noisy
vibrations on to its other
side. And last, it should
help isolate sound (Fig. D)
so vibrations aren’t directly
passed on from one object
or place to another. There
are a few other facts (and
misconceptions) about
noise that are important to
understand.

Although fiberglass and
other types of insulation
are great heat and cold
insulators, they’re fairly
mediocre sound insulators.
They lack mass. Fiberglass
insulation will help reduce
noise transmission
through exterior and interior
walls when meticulously
cut and fitted
around and behind wires,
pipes and electrical boxes.
But to be even moderately
effective, all holes and
cracks must be sealed with
a heavy material like caulk
or plaster. And to be really
effective, fiberglass insulation
needs to be coupled
with other methods used
for soundproofing a wall.

Metal beams, ducts and
pipes vibrate easily and
carry impact noises from
one end to the other. To
reduce noise, use rubber or
resilient materials to support
them. You can also
help confine noise by creating
a break in the material:
Install two short beams
with a small space between
instead of one long beam,
or install a rubber boot or
flex duct in the heating system
as shown in Fig. E.

Soft, dense materials, like
heavy curtains, stuffed furniture
and thick carpet, will
make the room they’re in
quieter and less echo-y and
slightly reduce the noise
transmitted to other rooms.

The concepts are pretty
simple. But things start getting
complicated when we
apply these ideas to our houses.

A Quiet Home vs. a Noisy Home

In a whimsical 1970s tune,“One Man’s Ceiling Is Another
Man’s Floor,” songwriter Paul Simon bemoaned the
noisy fate of apartment dwellers. But even those of us who
live in houses can relate to the gist of the song; the world
around us is noisy!

When Ray next door practices his duck calls at 7 a.m. or
your teenager practices her bassoon solo at 11 p.m. or a
jumbo 757 takes off over your house at dawn, you’d just as
soon hear the sounds of silence.

Here we’ll explain the basics of noise transmission, plus give you some ideas on how to make your home quieter.

Noise travels easily through gaps,
cracks and lightweight building materials
that lack mass. The homeowner on the
left, with brick siding, snug-fitting storm
windows, a well-caulked exterior and
other sound-blocking measures, will
wake up better rested and a lot less
crabby than the guy on the right.

A very quiet, very uncomfortable solid concrete home

Taking things to an
extreme, you could build a
house that would shut out
most outside noise. You
could erect four solid concrete
walls on a concrete
slab, cap them with a concrete
roof, then cover the
whole house with earth.
The concrete wouldn’t
have gaps for sound to slip
through, the massive walls
wouldn’t vibrate and pass
on outside noise, and the
earth would isolate the
house from impact-type
noises. You could catch
some serious ZZZZs in a
house like that.

But you’d need a way
in, so you’d add a door.
And you’d want light and
fresh air, so you’d add windows.
And you’d cut in
vents for your dryer and
bath fan; you’d add a chimney
for your furnace. And
since concrete walls aren’t
all that homey, you might
replace one or two with
wood-framed walls with
cedar siding and knotty
pine paneling. All of a sudden,
your solid, quiet
house contains holes and
“thin spots” that sound can
travel through. And, of
course, the people inside
your silent dream home
aren’t always quiet either.
Bammm, welcome to
Noise Town, U.S.A.

As you can see, efforts
to create a quieter home
are always a compromise
of function, looks, convenience,
comfort and cost.
Here are some steps you
can take to create a quieter
home. Some only
make sense when
done in the course
of a major
remodeling
project; others
can be
done any time.

How to hush outside noise

Outside noise can be the
most annoying because it
“belongs to someone
else.” It can also
be startling. There’s a logical
order to follow in
blocking outside noise;
you’ll be wasting your time
doing things further down
this list until you take care
of the higher-up essentials.
One nice bonus about
these soundproofing measures
is they’ll often lower
your heating and cooling
bills to boot.

You should:

Seal up holes and cracks.
Be extremely thorough.
Noise will infiltrate even
the slimmest gaps,
negating other soundblocking
measures you
take. Use flexible
polyurethane or latex
caulk to seal cracks and
gaps around windows,
doors and siding. Pack
putty or squirt expanding
foam around pipes and
wires where they enter the
house. Noise reduction
programs designed to
reduce noise levels in
homes near airports even
recommend extremes like
sealing off a mail slot and
using a mailbox instead.
It’s these simple steps that
will give the most reduced
bang for your buck.

Tighten up existing door
and window openings.
Thoroughly weatherstrip
all four sides of existing
doors and windows. Install
a solid-core door, which
will block more sound than
a foam-core door or a door
with glass panels.

Install high-quality
storm windows. Those
with thick glass, sturdy
frames and good weather stripping will be the most
effective at blocking
sound. The wider the airspace
between primary
and storm windows (3 to 4
in. is great), the better the
sound blockage. Doublehung
and glider windows
are easily fitted with storm
windows; crank-out casement
windows are best fitted
with one-piece, interior
magnetic windows.
Install good, solid storm
doors on all your exterior
doors.

Add insulation to the
attic and walls. Meticulously
installed fiberglass
batt or blown-in insulation
will help reduce noise
levels.

Add central air conditioning.
It will allow you to
remove window-style units
and keep your windows
shut against noise.

Add mass to walls. If one
wall faces a busy, noisy
street, add mass in the
form of drywall, as
explained in the next section.
Trees, hedges and
fences provide psychological
relief by blocking noise
sources from view. But
since they lack mass, they won’t block much noise.

How to hush general interior noise

To quiet footsteps and
impact noises from rooms
above, install carpet with a
thick pad in the upper
room and a suspended
ceiling with heavy rigid
board (not flexible fiberglass)
ceiling tiles in the
lower room. Drywall can
be cemented to the top of
standard ceiling tiles to add
mass—just make certain
the metal grid can support
the added weight.

Limit noise traveling
between adjacent rooms by
caulking around all outlets
and switch boxes, especially
those that are back to
back. Replace hollow-core
doors with solid-core
doors and install weatherstripping
and a bottom
sweep just as you would
with an exterior door.

To create a true quiet
zone, add mass in the form
of an extra layer of drywall
and isolate that mass by
one of two methods. The
first is to screw resilient
drywall channels horizontally
across walls and add a
second layer of 5/8-in. drywall
(Fig. E). The second
method, for ultimate quiet,
is to build a separate 2x4
wall, insulate the cavity,
drywall both sides, then
erect it 1 in. away from the
existing wall (to isolate it).
Adding drywall usually
means that you have to
move outlet and switch
boxes (or add box extenders)
so they’re flush with
the new surface. To make
door and window trim fit
right, you’ll have to add
extension jambs, another
labor-intensive job.

How to hush appliances and mechanical systems

Heating and plumbing systems
are double trouble
since they both create and
distribute noise. Most of
the following products are
available at heating and
cooling as well as
plumbing supply
houses.

To limit heating and
cooling system noise:

Replace a short section
of the round
metal duct leading to each
heat register with insulated,
sound-absorbing
flexible duct (Fig. E) to help
isolate furnace rumble
from the rest of the house.

Cut out and remove a
6-in. section from the main
plenum and replace it with
a rubber boot to further
isolate noise (Fig. E).

Install a separate run of
ductwork from the trunk
line for each register. Heat
registers sharing the same
duct and positioned back
to back or directly on top
of one another provide a
wide-open freeway for
sound to travel.

To limit plumbing noise:

If your copper pipes
clunk when your washing
machine or dishwasher
valves quickly shut off the
water supply, install water
hammer arresters to
absorb the shock (Fig. E).
Both whole-house and
individual fixture arresters
are available. They’ll create
a cushion to take the hammering
action out of your
pipes.

Use pipe isolators and
pipe hangers(Fig. E), available
at home centers, to cut
down on vibration created
by
running water.

Check the flexible supply
tube on noisy faucets or
toilets; water passing
through a kink or crimp
can be very noisy.

Replace noisy sections of
lightweight PVC drainpipe
with cast iron pipe (Fig. E).
Or wrap the PVC pipe with
thick layers of dense carpet
pad, then tightly pack the
joist or stud cavity with
insulation. Gurgling, flowing
PVC drainpipes can
sound especially unpleasant
if they run through
your dining room or
kitchen ceiling.

To limit appliance and
ventilation noise:

Space refrigerators, dryers
and washing machines
away from walls so the
walls don’t pick up and
amplify the sound.

Isolate washing
machines and dryers from
the floor by placing a
resilient material such as
rubber or cork pads under
each foot (Fig. D). Keep the
machines balanced by
adjusting the leg levelers.

Buy a quieter dishwasher,
bathroom fan or
kitchen stove vent when it
comes time to replace
them. Compare noise ratings,
or sone levels, as you
shop; the lower the number,
the quieter the unit. If
the numbers aren’t available,
use your ears on a
demo model on the sales
floor.